Folk Psychology and Mental Simulation*

*To appear in Contemporary Issues in the Philosophy of Mind, edited
by Anthony O'Hear, Royal Institute of Philosophy, Supplement 42 (Cambridge
University Press)

This paper is about the contemporary debate concerning folk psychology
the debate between the proponents of the theory theory of folk psychology
and the friends of the simulation alternative.{1} At the outset, we need to ask: What should we mean
by this term `folk psychology'?

Shall we perhaps say that folk psychology is just what the folk know
(or believe) about psychological matters? The problem with this putative
definition is that, if folk psychology is a body of known or believed propositions
about psychology, then it may be said that folk psychology is a psychological
theory. This would threaten to render invisible even the possibility of
an alternative to the theory theory of folk psychology.

Someone might respond to this problem by saying that not just any collection
of propositions about psychology deserves to be called a theory.
Only a set of propositions organised around generalisations that support
counterfactuals and are appropriately objective will earn that title.{2} So, folk psychology will be
a theory only if what the folk know or believe about psychology has something
of the character of a science. This response has some plausibility. There
is surely something to be said for this restrictive use of the term `theory',
and it will be important in Sectionof this paper, when we consider explanation
and understanding. But many of the participants in the debate between the
theory theory and the simulation alternative have used the term `theory'
in an extremely inclusive way. For example, Stephen Stich and Shaun Nichols
adopt a `wide interpretation' of the term on which `just about any internally
stored body of information about a given domain [counts] as an internally
represented theory of that domain'. {3} Our initial aim is to describe the debate or at least
one aspect of the debate in a way that takes account of the use of the term
`theory' to include any body of knowledge, belief, or information.

Instead of beginning with folk psychology as what the folk know or believe
about psychology, we do better to start with folk psychological practice
a practice in which we all engage on an everyday basis. We describe
people as bearers of psychological states. We explain people's behaviour
(or decisions, or judgements, or other psychological states) by appeal to
their psychological states. We predict people's behaviour (or decisions,
or judgements, or other psychological states) by relying on assumptions
about their psychological states. The debate between the theory theory and
the simulation alternative can then be seen as a debate about this three-stranded
practice. {4}

Amongst the many questions that can be asked about folk psychological
practice, one question that has been central in much of the recent literature
is the basis question: What is the basis of our ability to engage
in folk psychological practice?{5}
Indeed, a great deal of attention has been focused on the basis question
applied to just the prediction strand of folk psychological practice. The
greater part of this paper shares this relatively narrow focus (Sections
1 and 2). Only in the final section do we move to consider explanation and
understanding.

1. Prediction, Theory and Simulation

What would be the theory theory's account of folk psychological prediction,
and what alternative account would the simulation theory offer? We approach
the question indirectly by considering first a case of prediction in a straightforwardly
physical domain. How could someone predict the change in pressure of the
gas in a cylinder when its temperature is raised?

1.1 Prediction in a physical domain

One possibility would be to use an empirical generalisation about the
way in which the pressure of a volume of gas increases as its temperature
increases. {6} In this
case, the predictor would be drawing on a body of information about gases,
in line with a theory theory account. Another possibility would be to draw
on a theory about the movement and energy of gas molecules. By considering
the forces exerted on the walls of the cylinder, the predictor might arrive
at a prediction of increased pressure without actually having antecedent
knowledge of the temperature-pressure law. Or again, the predictor might
not draw on any knowledge about gases in general, but simply make use of
a formula relating the temperature and pressure of the gas in this particular
cylinder. Given the inclusive notion of theory that is in play, this too
would count as use of a theory.

There is, of course, an alternative to these theory-based strategies
for arriving at a prediction about the pressure of the gas in a cylinder,
A, after its temperature is raised. We could take another similar cylinder
of gas, B, heat it to the temperature in question, and measure the pressure.
Provided that the cylinder B really is relevantly similar to cylinder A,
this method is liable to yield an accurate prediction. By using the behaviour
of the second cylinder of gas as a simulation of the behaviour of
the first cylinder, we can make a prediction about cylinder A in the absence
of any antecedent empirical knowledge about changes in the behaviour of
gases under increases in temperature.

In order to use simulation in this way to predict the pressure in gas
cylinder A, we need to use another real gas cylinder and we need to raise
its temperature in reality. This simulation in reality provides for
prediction in the absence of antecedent empirical knowledge about the behaviour
of gases. A predictor who did not have a second cylinder to hand could,
of course, imagine having a second gas cylinder. Or a predictor who
was armed with a second gas cylinder but did not want to heat it could imagine
its temperature being raised. But in order for either of these imaginative
strategies to yield a prediction about the pressure in cylinder A, the predictor
would need to develop the imagined gas cylinder narrative beyond its starting
point (`There is a cylinder of gas. It is heated up. And then . . . ); and
to do this, the predictor would need to draw on some theory some body of
information about the behaviour of gases.{7} As a strategy for predicting the pressure in cylinder
A, simulation in imagination must deploy essentially the same resources
as those that are used according to the theory theory account. So, in this
case at least, simulation in imagination is theory-driven simulation.{8} It is only simulation in reality
that constitutes a genuine alternative to the use of empirical theory in
prediction.

1.2 Psychological prediction

In the folk psychological case, it is clear enough how knowledge of an
empirical theory about psychological matters can yield predictions. The
body of theory drawn on might consist of some relatively superficial generalisations
about (personal level) psychological properties (cf.laws relating temperature,
pressure and volume of gases) or postulates about (subpersonal level) information
processing apparatus (cf.about the movement and energy of gas molecules);
or it might be information that is specifically about a particular individual
(e.g.whom the predictor knows well; cf.formula linking temperature and pressure
in cylinder A).

It is also clear that, in the psychological case, simulation in reality
can be an effective way of generating predictions without relying on knowledge
of empirical theory. Suppose that I want to predict (i)a person C will feel
(or how soon C will fall over) after drinking a pint of whisky, or (ii)the
Müller-Lyer illusion will look to C, or (iii)C will feel and what he
will decide to do if he is suspended over a cliff on a rope and he cannot
find a foothold and his hands are starting to slip, or (iv)C will draw the
conclusion that something is white from his belief that snow is white. {9} In each case, I can use the
strategy of placing another person, D, into the same situation and observing
D's reactions. This may well yield a correct prediction about C, provided
that C and D are relevantly similar ((i)the way that alcohol affects their
bodily constitution; (ii)the way that their visual systems work; (iii)the
way that they experience and act on emotions; (iv)the way that they reason).
To the extent that I, myself, am relevantly similar to C, I have an option
that is not available to me in the case of gas cylinder simulation in reality;
namely, I can place myself into those situations and observe my own reactions.
I drink a pint of whisky, or look at the two lines, or dangle perilously
over a cliff, or draw out some simple inferences from my belief that snow
is white. Indeed, in discussions of mental simulation in reality, it is
usually this option of using oneself in a simulation that is considered.{10}

But it is mental simulation in imagination that is central for
the simulation theory. We saw that gas cylinder simulation in imagination
needs to be driven by empirical theory. Does the same go for mental simulation?
It seems clear that if, with a view to making a prediction about C, I imagine
placing another person D into the same situation, then I shall need to draw
on theory in order to develop the simulation beyond this starting point.
But if what I imagine is actually being in the situation,{11} then simulation in imagination
might allow a prediction about C to be generated. What this prospect seems
to depend on is the possibility that my imagining being in a situation engages
the same psychological or mental processes in me as would be operative if
I were really in that situation.

Consider, then, the conditions under which simulation in imagination
would yield correct predictions in the four sample cases that we have mentioned.
(i)simulation in imagination is to yield a correct prediction about how
C will feel after drinking a pint of whisky, then imagining drinking a pint
of whisky must produce in me feelings of giddiness leading to a fall or
at least imagined feelings of giddiness leading to an imagined fall. (ii)the
case of the Müller-Lyer illusion, imagining the two lines and the arrowheads
must lead to a visual experience real or imagined as of one line being longer
than the other. (iii)I imagine being suspended over a cliff on a rope, this
act of imagination must lead to real or imagined feelings of fear and panic.
(iv)I imagine believing that snow is white (or, more to the point, when
I imagine believing that, say, butter is white something that I do not,
in reality, believe), this must lead to the real or imagined act of judging
that something is white.

We take it that the facts about these cases are roughly as follows. (i)drinking
a pint of whisky does not, in and of itself, produce real or imagined feelings
of giddiness. The bodily processes that lead up to a feeling of giddiness
are not engaged by the imagined consumption of alcohol in the same way that
they would be engaged by the real consumption of alcohol. If my simulation
in imagination does move forward from the drinking to the feelings, then
this is because I am bringing to bear some empirical knowledge about how
people typically feel or about how I usually feel after consuming large
quantities of alcohol.

(ii) the lines and the arrowheads does not, in and of itself, generate
the Müller-Lyer illusion in imagination. The visual processes that
give rise to the illusion are not engaged by the imagined confrontation
with that array of lines and arrowheads in the same way that they would
be by the real presentation of the array. (iii)the other hand, imagining
being in that dangerous situation, dangling at the end of a rope, may well
lead to real feelings of fear or panic, without my drawing on any empirical
theory about how people in that kind of situation typically feel. Imagined
danger may engage a range of bodily and emotional processes in somewhat
the same way that real danger does.

(iv) Finally, imagining believing the premises of an argument (that butter
is white) certainly can lead me to an imagined judgement of the conclusion
(that something is white), without my using any antecedently known empirical
theory about how people typically reason. There is an important contrast
between the case of reasoning from imagined beliefs and the case of emotional
response to imagined danger. The bodily symptoms of fear or panic may well
be real, even though the danger is only imagined. But in the case of reasoning,
if my commitment to the premises is only an imagined commitment, then my
judgement of the conclusion is similarly imagined rather than real. The
process leading from one to the other is, however, real, and not merely
imaginary, reasoning; and that real reasoning may also prompt a real judgement,
namely, the conditional judgement that if the premises were true then so
would be the conclusion.

What all this suggests is that the prospects for psychological prediction
by simulation in imagination, without the use of empirical theory, are not
utterly forlorn. It may also seem to suggest that we need to set about the
task of cataloguing which psychological processes are engaged in the same
way by imagined inputs as by real inputs. But while real interest and importance
would attach to that cataloguing project, it is also important to note that
it is not just a brute fact that imagining premises engages our reasoning
abilities in the same way that really believing the premises does.{12} Rather, the explanation of
this fact is that reason relations (such as entailment relations) obtain,
and are known by any thinker to obtain, amongst imagined or hypothesised
thought contents, in just the same way that they obtain amongst believed
thought contents. When I simulate C's reasoning in imagination, a theory
may well be used. But it is not an empirical theory about how people happen
typically to reason. Rather, it is a normative theory about right reasoning;
and it is the very same theory that I can use when I engage in reasoning
from premises that I actually believe.{13}

Although the simulation of reasoning may involve deployment of normative
principles, the simulation theory is not (even when restricted to reasoning)
to be equated with what might be called the normative theory theory.
It is possible to know normative principles relating to an activity in which
one does not, oneself, engage. But the simulation theory is clearly not
proposing that we make predictions by the disengaged use of a set of normative
principles about reasoning.{14}
Rather, normative principles may be used in simulation because they are
already available to us when we ourselves engage in reasoning. When we use
those normative principles, our reasoning becomes what Tyler Burge describes
as critical reasoning.

Critical reasoning is reasoning that involves an ability to recognise
and effectively employ reasonable criticism or support for reasons and
reasoning. It is reasoning guided by an appreciation, use, and assessment
of reasons and reasoning as such. As a critical reasoner, one not only
reasons. One recognises reasons as reasons. . . .

Essential to carrying out critical reasoning is using one's knowledge
of what constitutes good reasons to guide one's actual first-order reasoning.{15}

Not all reasoning is critical reasoning. But it is arguable that the
possibility of critical reasoning is an essential part of normal adult reasoning
as we know it.{16}

The point we have reached is that predicting the conclusions of another
person's (theoretical or practical) reasoning appears to be a particularly
favourable case for a simulation theory answer to the basis question about
the prediction strand of folk psychological practice. Of course, in order
to reach a correct prediction about C's conclusions by simulating his reasoning
in imagination, I need to take account of differences between C and myself.
If C believes that butter is white, while I do not, then C may arrive at
the judgement that butter and snow are the same colour, given that snow
is white, whereas I would not myself draw that conclusion. But I can take
account of this difference between C and me within the simulation, without
needing to draw on any empirical information about how people who believe
that butter is white tend to reason. Rather, in imagination I take on the
belief that butter is white and then, given the premises that snow is white
and that butter is white, I conclude that butter and snow are the same colour.
That is what right reasoning requires.

Predicting how someone will feel after drinking a pint of whisky, in
contrast, is a good case for a theory theory answer to the basis question.
Consequently, predicting the conclusions that will be reached by someone
reasoning after drinking a pint of whisky also depends on at least some
contribution from empirical theory. If C has just drunk a pint of whisky
and I have not, then I need to take account of this difference between him
and me when I try to simulate his reasoning in imagination. Even if I correctly
take on C's premises in imagination and imagine drinking a pint of
whisky, still my predictions about C's conclusions are liable to be incorrect,
unless I bring to bear some empirical information about how whisky affects
(C's) reasoning. Here, correct prediction requires an intrusion of theory.
But this is not to say that, in the case of the inebriated C, my prediction
strategy must owe everything to empirical theory and nothing to mental simulation.
The empirical information that I draw on might take the form of information
about the ways in which someone in C's condition is liable to depart from
right reasoning. In that case, I could first use my own reasoning ability
to work out what would be a correct conclusion to draw from C's premises
and then tweak my prediction in the light of that empirical information.

1.3 The epistemology of prediction by simulation

Let us now consider, in a little more detail, how prediction by simulation
would work. We have already noted that, in the case of the gas cylinders,
prediction by simulation in reality relies on some assumption of relevant
similarity between cylinder B and cylinder A. One form that this assumption
can take is that cylinder B is a typical member of a class, G, of gas cylinders
of which A is also a member. Heating the gas in cylinder B and measuring
its pressure can then be conceived as an experiment, licensing a
general claim about temperature and pressure in gas cylinders in the class
G. Since cylinder A is assumed to be a member of this class, the experimentally
licensed generalisation can be applied to it. Essentially the same kind
of account could be given, in the psychological case, of the role of the
assumption of relevant similarity between person D and person C. And if,
in a case of mental simulation in reality, I use myself instead of another
person D, then an assumption of relevant similarity between me and C plays
the same role again. Placing myself in the situation can be conceived as
an experiment.

It would seem plausible, then, that there is no very deep difference
between the epistemological status of predictions based on simulation and
predictions that rely on experimentally licensed knowledge of empirical
generalisations. Furthermore, it would appear that, in the case of mental
simulation in imagination, much the same account would be given, but with
an extra empirical assumption to the effect that the processes in me that
are engaged by imagined inputs work in the same way as the processes in
me, and in C, that are engaged by real inputs. The cataloguing project mentioned
several paragraphs back in Section 1.2 would then be seen as the project
of assessing the extent to which that empirical assumption is warranted.

However, the account that we have sketched of simulation of reasoning
in imagination may open the possibility of a distinctive epistemology of
psychological prediction. What the normative theory of right reasoning tells
the simulator is that the conclusion say, that something is white is the
right thing to think, given the premise say, that snow is white, or that
butter is white. This normative judgement about what is the thing to think
does not, by itself, yield a prediction about C, of course. The simulator
also needs an assumption that C will think the thing that is the thing to
think. That is a defeasible assumption in any given case. But it may enjoy
a default status, nevertheless, since unexplained departures from these
normative requirements of reasoning call in question our attributions to
C of thoughts with such contents as that snow is white or that butter is
white.{17} This route
to prediction goes via a normative judgement (this is the thing to think
in such-and-such a situation) and an assumption about interpretation (C
will think the thing that is the thing to think). It is to be contrasted
with a route that goes via an empirical judgement (this is what I think
when placed experimentally in such-and-such a situation) and an assumption
of similarity (C is relevantly like me).

2. Prediction Failure

We have distinguished between simulation in reality and simulation in
imagination as methods of prediction. Simulation in reality can certainly
be an effective way of generating predictions without relying on empirical
knowledge. But the prospects for prediction by simulation in imagination
depend on the possibility that imagining being in a situation should engage
the same psychological or mental processes as would be operative if one
were really in that situation. We considered a range of examples and concluded
that predicting the results of another person's reasoning is a good case
for simulation in imagination while predicting how someone will feel after
drinking a pint of whisky is not. But while it might be agreed that predicting
the conclusions of reasoning could be achieved by mental simulation, this
does not settle the question whether prediction is in fact achieved in that
way. Perhaps, despite the availability of simulation, we ordinarily make
such predictions by relying on an empirical theory about how people reason.

The basis question with which we began is an empirical question about
our three-stranded folk psychological practice, and we have been focusing
on the question as it applies to the prediction strand. But we have so far
said nothing about the kinds of empirical evidence that would count in favour
of one or another answer to the basis question. In a series of important
papers, Stich and Nichols have urged that the phenomenon of prediction
failure is strong evidence in support of a theory theory answer to the
question about the basis of our prediction practice.{18}

In our everyday folk psychological practice, we sometimes make wrong
predictions. Stich and Nichols argue that this happens because our prediction
method is cognitively penetrable that is, our psychological predictions
are influenced by our antecedent knowledge or beliefs about the psychological
domain. This kind of explanation of prediction failure is available to the
theory theorist but unavailable, Stich and Nichols say, to the friend of
mental simulation. So the existence of prediction failure is a crucial test
of the empirical adequacy of the two competing accounts of the causal basis
of our prediction practice, and favours the theory theory account. Thus,
on the one hand:

One virtue of using a simulation to predict the behaviour of a system
is that you need have no serious idea about the principles governing the
target system. You just run the simulation and watch what happens. . .
. In predictions based on simulation, what you don't know won't hurt you.
. . . If there is some quirk of the human decision-making system, something
quite unknown to most people that leads the system to behave in an unexpected
way in certain circumstances, the accuracy of prediction based on simulations
should not be adversely affected. If you provide the simulation with the
right pretend input, it should simulate (and thus predict) the unexpected
output.{19}

But, on the other hand:

Just the opposite is true for predictions that rely on a theory. If
we are making predictions on the basis of a set of laws or principles,
and if there are some unexpected aspects of the system's behaviour that
are not captured by our principles, then our predictions about those aspects
of the system's behavior should be less accurate. Theory based predictions
are sensitive to what we know and don't know about the laws that govern
the system; they are cognitively penetrable.{20}

The dialectical situation that Stich and Nichols sketch is especially
clear when we contrast theory-based prediction and prediction by simulation
in reality. Thus, consider again our prediction of the pressure in gas cylinder
A. If someone has a false theory about the behaviour of gases, then a theory-based
prediction about cylinder A is liable to be false. But, if the predictor
uses the behaviour of cylinder B as a simulation of the behaviour of cylinder
A, then the prediction arrived at should be correct. Because the prediction
method does not draw on any antecedently believed empirical theory about
the behaviour of gases, the prediction can, in principle, be insulated from
any false theoretical beliefs that are antecedently held by the predictor.{21}If someone makes an incorrect
prediction about the pressure of the gas in cylinder A after it has been
heated then either the predictor is not using simulation as the prediction
method or else the simulation is flawed in one of two ways. It may be that
cylinder B is not relevantly similar to cylinder A or it may be that the
gas in cylinder B was not heated to the correct temperature.{22}

In the psychological case, just the same points can be made. If, in order
to arrive at a prediction about C, I use D (or myself) for a simulation
in reality, then the prediction should be correct. If it is incorrect then
either D is not relevantly similar to C (or I am not similar to C), or else
D (or I) was not placed into the correct situation (that is, the simulation
was not provided with the correct inputs). But the central case of mental
simulation is simulation in imagination. Is the dialectical situation the
same here? There is some reason to allow that it is. Someone who claims
that mental simulation provides even a possible account of folk psychological
prediction relies on the idea that imagining being in a situation may engage
the same psychological or mental processes as would be operative if one
were really in that situation. For some examples, such as the situation
in which one drinks a pint of whisky, the idea has no plausibility. But
the advocate of mental simulation has to maintain that there are other cases
where the idea is plausible, and we have suggested that these would include
cases of theoretical and practical reasoning. So, it appears that prediction
failure relating to reasoning would present a problem for anyone offering
a mental simulation answer to the basis question about folk psychological
prediction. Certainly, this is what Stich and Nichols have argued; and they
have gone on to present examples of this kind of prediction failure.

2.1 Examples of prediction failure

There is no shortage of surprising experimental psychological data about
conclusions that people draw and decisions that they take. The very fact
that we find the data surprising indicates, of course, that we ourselves
would have made incorrect predictions about what the subjects in the experiments
would conclude or what they would decide. We shall describe two of these
examples.{23}

Position effects: right bias in selecting goods

Shoppers are presented with a display of what are, in fact, identical
samples of some product. They are asked to assess the quality of these samples
and then by way of payment for participating in the survey to select one
sample to keep. The result is that the shoppers' selections show a bias
towards samples near the right hand end of the display over samples near
the left hand end.{24}

Most people are surprised to hear the result of this experiment; they
would predict that shoppers' selections would be random. If these predictions
are arrived at by mental simulation, then simulation is generating incorrect
predictions. Yet it is reasonable to assume that the people who are asked
to predict the outcome of the experiment are relevantly similar to the subjects
in the experiment (the shoppers).

The Langer effect

Two groups of subjects are sold lottery tickets for $1 each. Subjects
in one group are allowed to choose their lottery ticket (choice condition);
subjects in the other group are simply given a ticket (no-choice condition).
Subjects are then (under some pretext or other) asked to be ready to sell
their ticket back to the experimenter, and are asked to set a sell-back
price. The result is that subjects in the choice condition set very much
higher prices on average than subjects in the no-choice condition (over
$8 versus just under $2).{25}

Most people are surprised to hear the result of this experiment. For
example, Stich and Nichols report anecdotal evidence of presenting undergraduate
students with a description of the experiment and asking them to predict
what the subjects would do. The students failed to predict the difference
between the sell-back prices set by subjects in the choice condition and
subjects in the no-choice condition. If these predictions are arrived at
by mental simulation the students simulating first being in one condition
and then being in the other then simulation is generating incorrect predictions.
Yet it is reasonable to assume that the students who are asked to predict
the outcome of the experiment are relevantly similar to the original subjects.

2.2 Response on behalf of the simulation theory

Given the way that the argument about prediction failure has been set
up, it will appear that the defender of mental simulation is bound to make
a move analogous to saying that gas cylinder B was not heated to the correct
temperature. That is, the defender of simulation must say that, in these
cases of prediction failure, the (pretended) inputs to the predictor's simulation
in imagination are in crucial respects different from the inputs that engaged
the psychological processes of the subjects in the real experiments. This
is, indeed, the way in which advocates of mental simulation have responded.

Thus, for example, Robert Gordon comments on the example of right bias
in selecting goods that, `unlike the subjects in the original experiment,
the subject in the imagination experiment [the person trying to predict
how shoppers will behave] must be told that the items on display are identical
(and thus of equal quality)'.{26}
In a similar vein, Paul Harris notes that a person trying to predict the
outcome of the Langer experiment using simulation:

needs to simulate the vacillation and eventual commitment of the free-choice
subjects. Moreover, in making that simulation they must also set aside
the tacit reminder embedded in a narrative that juxtaposes the two groups
of subjects, namely that any lottery ticket whether selected or allocated,
has the same likelihood of winning. Subjects in the experiment who were
offered a free choice had no knowledge of the other group, and by implication,
no such tacit reminder.{27}

This is a good initial move to make on behalf of the simulation theory.
Someone who is aiming to make a prediction by simulation in imagination
must imagine being in the very situation that the subjects in the original
experiment were in. And this must be done in such a way as to offer the
simulator's psychological processes inputs that are equivalent to the inputs
that engaged the original subjects' psychological processes. In a case of
simulation of reasoning, the simulator must take on in imagination the very
same premises that were available to the original subject. But, as Gordon
and Harris point out, the way in which the experimental situation is described
may prevent this condition from being met.

There is a quite general point here; namely, that the way in which the
situation to be imagined is described can make a huge difference to the
prospects for successful simulation. Consider the case of a lexical decision
experiment. Letter strings are flashed up on a computer screen some strings
form real words, and some form (pronounceable) non-words. The subject has
to decide whether each letter string is a word or a non-word and press one
or another button to indicate this decision. Suppose that I am asked to
predict what decisions subjects will make. Simulation in reality is no problem
here: I can just sit in front of the screen myself. But if I have to simulate
this experimental regime in imagination, then some ways of describing the
input make my task nearly impossible. I might, for example, be given a description
of the screen display in terms of the pattern of light and dark pixels that
form the image of the letter string. If, on the other hand, the screen display
is described by the letters being named in order, then I may very well be
successful in simulating the performance of subjects in the experiment and
thus predicting their responses. This successful prediction would not seem
to depend on antecedent knowledge about how normal subjects respond to this
or that letter string in a lexical decision experiment. Rather, I would
just make what I take to be the correct decision about each imagined letter
string, and then assume that other subjects would make the correct decision
too. In doing this, I would make use of stored information; but it would
be information about lexical items, not information about normal subjects'
lexical decisions.

In our view, this line of response (in terms of wrong inputs)
enables the simulation theorist to fend off the initial versions of the
objection from prediction failure. But it does not resolve the debate in
favour of either side because the response simply invites the theory theorist
to improve the design of the prediction experiment so as to rule out the
wrong inputs response. Thus, for example, Nichols, Stich, Leslie and Klein
report a prediction experiment in which subjects in one group watch a videotape
of a subject in the choice condition of a Langer-style experiment and are
asked to predict the subject's sell-back price, while subjects in another
group similarly watch a videotape of a subject in the no-choice condition.{28} As in the original Langer
experiment, subjects in the choice condition set significantly higher sell-back
prices than subjects in the no-choice condition. But there was no significant
difference between the prices predicted by subjects shown the choice condition
videotape and the prices predicted by subjects shown the video of the no-choice
condition. Thus, even with a videotape to help them imagine the experimental
situation, subjects are not reliably able to reach correct predictions.

There is no doubt that discussion of these examples can be continued,
with the defender of prediction by mental simulation in imagination deploying
variations on the wrong inputs theme.{29}But there is a slightly different kind of response to
these examples that is suggested by our earlier reflections on the prospects
for psychological prediction by simulation in imagination (Section 1.2).

2.3 The circumscribed domain of prediction by mental simulation

There are all kinds of factors that may affect a person's theoretical
or practical reasoning, such as whether the person believes that butter
is white, or whether the person has just drunk a pint of whisky. Some of
these factors can readily be taken into account by someone attempting a
prediction by mental simulation in imagination, while others cannot. Showing
me a videotape of a subject drinking a pint of whisky before engaging in
some reasoning will not enable me to predict the outcome of the subject's
reasoning, however accurately I may imagine the subject's situation. As
we noted in Section 1.2, what I need is empirical information about the
effects of whisky drinking.{30}
(Recall, too, that the use of this empirical information need not wholly
supplant engagement in mental simulation.)

The fact that prediction by mental simulation in imagination requires
an intrusion of theory in such cases of `non-rational' influences has been
recognised from the beginning of the contemporary debate.{31} Furthermore, it seems quite likely
that some of the factors at work in producing the Langer effect or the right
bias in selecting goods may be more like whisky than like reasons. For example,
most people who are told about the position effects experiment find it surprising
that the shoppers' selections show a bias towards samples near the right
hand end of the display. They would predict a random distribution of selections.
A plausible explanation for this prediction is that there is no evident
reason to make one selection rather than another; the fact that a sample
is towards the right hand end of the display scarcely constitutes a justification
for selecting that sample rather than any of the others.{32} It is not ad hoc, then, to maintain
that these examples of prediction failure fall outside the proper domain
of prediction by mental simulation unaided by empirical theory.

A narrow circumscription of this domain is explicit in Heal's work:

The kind of simulationism I would like to defend says that the only
cases that the simulationist should confidently claim are those where (a)starting
point is an item or collection of items with content, (b)outcome is a further
item with content, and (c) latter content is rationally or intelligibly
linked to that of the earlier item(s).{33}

But her proposal faces an objection. In many cases of prediction failure,
the subjects about whom the predictions are made seem to depart in some
way from right reasoning. But, in some other cases of equally flawed reasoning,
correct prediction seems to be quite straightforward. In these latter cases,
why do not the non-rational influences put the reasoning beyond the range
of prediction by mental simulation?

Consider an example discussed by Daniel Kahnemann and Amos Tversky.{34} At a flying school, instructors
adopt a policy of responding positively to good performance (such as successful
execution of complex manoeuvres) and negatively to bad performance. When
reviewing this policy, they note that pilots who do particularly well and
are praised are likely to perform less well next time, while pilots who
perform particularly badly and are criticised are likely to do better at
their next attempt. The instructors conclude that, contrary to what psychologists
tell us about positive reinforcement, rewarding good performance is not
an effective training method.

Most people find the flight instructors' conclusion to be quite unsurprising;
it is just as they would predict. Yet the instructors' reasoning is flawed;
it overlooks the phenomenon of regression towards the mean. (A pilot who
has reached a certain level of competence and performs outstandingly well
on one trial is likely to perform less well on the next trial, independently
of the reaction of the instructor.) Is this not a problem, the objector
asks, for the idea that the proper domain of prediction by mental simulation
is the domain of rational linkages?

It is clearly relevant to note, here, that the reasoning of the people
who successfully predict the instructors' conclusion is flawed in just the
same way as the reasoning of those instructors. But that point is liable
to suggest, again, that there is something wrong with the proposal to circumscribe
the proper domain of prediction by mental simulation in terms of the contrast
between right reasoning and non-rational influences. What matters for mental
simulation, the objector may say, is not rationality but similarity.{35} Prediction by mental simulation
will be successful just where a process that operates in imagination in
the predictor is relevantly similar to the process operating in reality
in the subject about whom the prediction is being made. By that account,
probabilistic reasoning that overlooks regression towards the mean falls
squarely within the proper domain of prediction by mental simulation, since
the error is one that virtually everyone is disposed to make.

Our view is that it is possible to defend Heal's circumscription of the
proper domain of mental simulation by drawing on two ideas from Section
1: the idea of a normative theory and the idea of a distinctive epistemology
of psychological prediction. First, as critical reasoners, we are each in
possession of a normative theory of right reasoning (Section 1.2). We are
also subject to non-rational influences and so we are all liable, on occasion,
to reason in ways that are out of line with our normative principles. However,
some departures from right reasoning may actually be sanctioned by our normative
principles; that is, our normative theory may itself be flawed. Second,
in virtue of our possession of a normative theory, we can arrive at judgements
about what is the thing to think in a certain situation; and we can use
those judgements, coupled with an assumption that the subject will think
the thing that is the thing to think, in order to arrive at predictions.
This predictive strategy can bestow a distinctive kind of epistemic warrant
(Section 1.3). When a subject departs from right reasoning in a way that
is out of line with our normative theory, this strategy will yield a wrong
prediction, and will need to be augmented by empirical information about
the non-rational influences at work on the subject. When the subject departs
from right reasoning in a way that is sanctioned by our normative theory,
in contrast, this strategy will yield a correct prediction. But it will
be a prediction that does not constitute knowledge, since it is based on
two false claims that this is the thing to think, and that the subject will
think the thing that is the thing to think where the error in the second
claim compensates for the error in the first.

On this account, if the predictor and the subject share an incorrect
normative theory then the predictions arrived at will be fortuitously, rather
than knowledgeably, correct. The narrowly circumscribed domain of mental
simulation is the domain of knowledgeable predictions that are arrived at
by that epistemologically distinctive route.

However, we should also consider what happens if the predictor learns
about the importance of not ignoring regression towards the mean. For now
the predictor will, provided that he or she is properly attentive, arrive
at a correct judgement about what is the thing for the flight instructors,
for example, to think. But the predictor may also recognise that, in this
kind of case, most people are apt not to think the thing that is the thing
to think. So, the predictor will take this empirical information into account
when arriving at a prediction about the flight instructors. It may be that
the informed predictor characterises the way in which most people depart
from right reasoning simply as the way in which he or she used to reason
before learning about regression towards the mean. Perhaps, indeed, the
predictor still finds it all too easy to slip back into that flawed pattern
of reasoning. In that case, the predictor may suspend his or her recently
acquired normative knowledge, and engage in a piece of not wholly critical
reasoning, so as to arrive at a correct and knowledgeably correct prediction
about the flight instructors.

This is quite properly regarded as a piece of prediction by mental simulation.
But the route that it takes is via an empirical judgement (this is what
I used to think how I used to reason) and an assumption of similarity (the
flight instructors are relevantly like me as I used to be). So, while the
distinctive epistemology of prediction that goes with the idea of a normative
theory of right reasoning is of some importance, it would be wrong for us
to suppose that all knowledgeable prediction by mental simulation exhibits
that distinctive epistemology.

3. Simulation, Explanation and Understanding

We began with the three strands of folk psychological practice description,
explanation, and prediction but we have been almost exclusively concerned
with folk psychological prediction, and with the basis question concerning
that strand of our practice. In this final section, we turn briefly to folk
psychological explanation.

3.1 Explanation and generalisations

Suppose that we want to explain the increase of pressure in our gas cylinder
that results from an increase in temperature. The theory theory account
of prediction (Section 1.1) can readily be converted into an account of
explanation by subsumption.{36}
The conjunction of an increase in temperature and an increase in pressure
is subsumed under the temperature-pressure law. The truth of this generalisation
is not, however, something brute. The relatively superficial temperature-pressure
law belongs, not only with a more general principle relating temperature,
pressure and volume, but also with a body of empirical theory about the
movement and energy of gas molecules, and about forces exerted on the walls
of the cylinder. In terms of this theory, it is possible to give a mechanistic
account of how it is that the relatively superficial law is true of how
the temperature-pressure connection is implemented. In short, according
to the theory theory account, prediction and explanation go naturally together,
and a predictor who knows not only the superficial generalisation but also
the broader body of theory is able to achieve an explanatory understanding
of the predicted increase in pressure.

In the folk psychological case, too, the theory theory account of prediction
goes along with an account of explanation. Knowledge of a body of psychological
theory provides the resources for explanations that work by subsuming events
under causal generalisations. There may be variations on this theme. Some
theory theorists will regard knowledge of relatively superficial psychological
generalisations as the visible tip of an iceberg of more elaborated tacit
knowledge, while others will commit themselves only to knowledge in the
ordinary sense of the term. Some theory theorists will regard cognitive
scientific theories about subpersonal level information processing machinery
as offering deeper explanations of psychological matters, while others will
hold hard to the personal level. But the general picture is clear.

Given that familiar picture of explanation by subsumption, it may seem
obvious that the basis question about the explanation strand of folk psychological
practice has a ready answer in terms of the theory theory, but cannot be
answered in terms of the simulation alternative. Explanation requires generalisations;
but mental simulation is supposed not to depend on antecedent knowledge
of psychological generalisations. However, what seems obvious is not quite
correct.

Consider again the case of the gas cylinders. We have noted already (Section
1.3) the similarity between prediction by simulation in reality and the
use of experiments to license generalisations. So, gas cylinder simulation,
carried out without antecedent knowledge about the behaviour of gases, could
yield knowledge of generalisations that could, in turn, be used in subsumptive
explanations. Gas cylinder simulation in reality would naturally be called
black box simulation; we simply give the simulation device (gas cylinder
B) a temperature as input and receive back from it a pressure as output.
Consistently with that description, the experimentally licensed generalisations
would be superficial and, because of the lack of explanatory depth, the
simulation would scarcely provide any explanatory understanding of the predicted
increase in pressure. But still, the basic point remains. Simulation, conceived
as experiment, may yield knowledge of generalisations under which events
can be subsumed. We could call this simulation-driven theory.

So also, in the folk psychological case, simulation can be regarded as
experiment and may yield knowledge of empirical generalisations. This is
particularly clear in the case of simulation in reality. By drinking pints
of whisky, looking at pairs of lines, dangling on ropes, and drawing inferences,
I may not only arrive at predictions about another person C (Section 1.2).
I may also, by induction from these bouts of simulation considered as experiments,
arrive at empirical generalisations under which events in the mental life
of C may be subsumed. This is also true though over a circumscribed domain
for mental simulation in imagination. When I simulate C's reasoning in imagination,
I draw on a normative, rather than an empirical, theory about reasoning.
But I may arrive at empirical generalisations by induction on the results
of simulation in imagination; and, to the extent that mental simulation
may yield correct predictions, it may also yield correct generalisations.{37}

3.2 Simulation and understanding

If explanation is conceived as subsumption under generalisations, then
the debate initiated by the basis question about the explanation strand
of folk psychological practice will take a course that is essentially parallel
to the debate over the prediction strand. But in fact, many advocates of
the simulation alternative would defend the idea that there is a distinctive
not straightforwardly subsumptive kind of explanation involved in folk psychological
understanding. Thus, for example, Heal says:

The difference between psychological explanation and explanation in
the natural sciences is that in giving a psychological explanation we render
the thought or behaviour of the other intelligible, we exhibit them as
having some point, some reason to be cited in their defence.{38}

This kind of normative explanation reveals what someone thought or did
as having been the rational thing to think or do, or the thing that it made
sense to think or do, given the circumstances and the agent's beliefs and
preferences. Clearly, explanation in this style fits together with our account
of prediction by mental simulation (in a circumscribed domain) in somewhat
the way that explanation by subsumption is the natural companion of prediction
that draws on empirical generalisations.

But we do not get an adequate view of the distinctive kind of psychological
understanding that might be provided by mental simulation if we focus only
on the normative aspect. For, as we have noted (Section 1.2), it is possible
to deploy a normative theory about an activity in which one does not, oneself,
engage. What mental simulation promises is a kind of understanding that
is not only normative but also first personal.{39} We see the combination of these two aspects most
vividly in the simulation of reasoning in imagination; and the idea that
mental simulation can provide a distinctive kind of understanding of another
person's reasoning is strikingly similar to R.G. Collingwood's claim that
historical understanding is to be achieved by the re-enactment of the historical
character's thought.

But how does the historian discern the thoughts which he is trying to
discover? There is only one way in which it can be done: by rethinking
them in his own mind. The historian of philosophy, reading Plato, is trying
to know what Plato thought, when he expressed himself in certain words.
The only way in which he can do this is by thinking it for himself. This,
in fact, is what we mean when we speak of `understanding' the words. So
the historian of politics or warfare, presented with an account of certain
actions done by Julius Caesar, tries to understand these actions, that
is, to discover what thoughts in Caesar's mind determined him to do them.
This implies envisaging for himself the situation in which Caesar stood,
and thinking for himself what Caesar thought about the situation and the
possible ways of dealing with it. The history of thought, . . . is the
re-enactment of past thought in the historian's own mind.{40}

Indeed, just as the domain of prediction and correlatively of understanding
by mental simulation may be narrowly circumscribed (Section 2.3), so also
understanding by re-enactment may seem to be restricted to right thinking.
This would be a severe limitation on historical understanding.

Patrick Gardiner considers this objection to Collingwood in a recent
paper:

[I]t may . . . be objected that the re-enactment conception of understanding
remains unrealistically restrictive in the amount it seems to exclude from
the historian's proper scope. However scrupulous the care taken to judge
an action from the agent's own standpoint, there can be no a priori
guarantee that the reasoning ascribable to him will turn out to have been
cogent or sound; as Francis Bacon once remarked, `it is a great mistake
to suppose men too rational'. It is always conceivable in principle, and
it is surely often the case in practice, that there is a lack of coincidence
between the conclusions people actually draw on the basis of their beliefs
and purposes and the conclusions that rationally they should have drawn.
Thus in history as elsewhere people may engage in faulty practical thinking,
whether because such things as haste or unimaginativeness or as a result
of underlying emotional factors that sway or distort their judgement. But
when that happens the objection may continue it does not follow that their
behaviour is unintelligible in terms of reasons, only that the reasons
are liable to be poor or inadequate ones.{41}

Gardiner's response to this objection is to note that `Collingwood would
be less vulnerable to some of the criticisms brought against him on the
present score if his conception [of re-thinking] were interpreted in a more
flexible manner'. On such an interpretation, re-enactment of thought would
cover not only right reasoning but also, for example, `empathetically appreciating
how an agent could have been tempted or misled into accepting a particular
practical conclusion without recognising the faultiness of the reasoning
involved'.{42} Is it
possible for a friend of mental simulation to expand the domain of understanding
by simulation in a similar way?

In the case of prediction by simulation (Section 1.2), we saw that there
could be an intrusion of empirical theory without the prediction strategy
coming to owe everything to theory and nothing to mental simulation. The
possibility that we mentioned there was that the empirical information drawn
on might be information about how particular influences (such as drinking
a pint of whisky) lead to departures from right reasoning. However, there
is no guarantee that, if we modulate the re-enactment of thought in the
light of empirical information, then the resulting first person narrative
(in imagination) will be one that we find intelligible. Thus, for example,
Simon Blackburn considers the case of deliberating about what is the thing
to do if one is a subject in Milgram's obedience experiment, and then taking
account of the empirical evidence about what subjects actually tend to do.
The simulator can modify his or her narrative in the light of the empirical
information. But, `this need have no tendency to make the behaviour of Milgram's
subjects intelligible. I might still feel quite baffled, both by them, and
if I am like them, by me.'{43}

An intrusion of empirical theory may, then, bring with it a loss of intelligibility.
But it would not be right to conclude that there is no prospect of a more
flexible conception of the domain of understanding by simulation. Consider,
for example, the predictor who now knows about regression towards the mean
but who still finds it all too easy to slip back into flawed reasoning (Section
2.3). This predictor will surely not be baffled by the reasoning of the
flight instructors. Their reasoning does not measure up to the informed
predictor's normative theory; but their first person narrative is nevertheless
one that the predictor will find intelligible.

There are other cases, too, in which it may be possible, without simply
being driven by an empirical theory, to re-enact thinking that departs from
right reasoning. Let us return to one of our earlier examples. I want to
predict how C will feel and what he will decide to do if he is suspended
over a cliff on a rope and he cannot find a foothold and his hands are starting
to slip (example (iii) in Section 1.2). Seized by fear or panic, C may not
think or do the best thing, the most rational thing. Yet, by simulating
C's situation in imagination, I might reach a correct prediction about C
without drawing on any empirical theory about how people dangling over cliffs
on ropes tend to think. For imagining the situation might be enough to produce
in me physiological and emotional responses that perturb my reasoning in
imagination in just the way that C's reasoning in reality is perturbed.{44} I might arrive at a correct
prediction about C; and if I regard the simulation exercise as an experiment
I might arrive by induction at some generalisations about how people think
and act in dangerous situations.{45}
But there is something more. By re-enacting C's desperate thinking, struggling
to maintain a grip, deciding to make another attempt to find a foothold
all in imagination, of course I surely gain some kind of empathetic understanding
of the thoughts, feelings and decisions that I predict. This is not a case
of theory-driven simulation; and it is not black box simulation either.
It is simulation that, in Gordon's phrase, `essentially engages [my] own
practical and emotional responses'.{46}

There is an alternative way in which I can gain a measure of first personal
understanding of C's thoughts, feelings and decisions a way that does not
require actual physiological and emotional responses in me at the moment
of understanding. I may take into account my own remembered similar experiences.{47} In this case, I draw on stored
information about how I felt, physically and emotionally, and about how
this affected my thinking and decision taking and I use this information
to help me imagine what it is like to be C. (I may also draw on memories
of imaginings in which I was fully physiologically and emotionally engaged.)
Producing a correct narrative about another person is not always sufficient
for finding what that person thinks and does to be intelligible. But it
is plausible that in some cases we can make sense of what someone thinks
and does by drawing on memory to help us imagine being in the other person's
situation indeed, to help us imagine being that person. This is an intrusion
of empirical theory, given the inclusive way in which the term `theory'
has been used. But it does not obstruct first personal understanding, and
it does not move us back towards explanation by subsumption.

Conclusion

In the first two sections of this paper we were concerned with the prediction
strand of folk psychological practice. The theory theory and the simulation
alternative agree about what folk psychological prediction is; but they
disagree about its basis. According to the theory theory, the predictor
draws on a body of information about psychological matters. According to
the simulation alternative, prediction is sometimes possible by simulation
in imagination without the aid of empirical psychological theory. However,
the domain of prediction by mental simulation particularly if the epistemology
is to be different from the epistemology of empirical theory is rather closely
circumscribed: it is the domain of reason.

When we turn to the explanation strand of folk psychological practice,
we find that the contours of the debate are very different. For there is
a disagreement about what folk psychological explanation is. According to
the theory theory, it is explanation by subsumption under causal generalisations.
So, if the basis of the explanation strand of folk psychological practice
is to be knowledge of a psychological theory, then that theory must contain
generalisations of the right kind objective, counterfactual supporting to
figure in subsumptive explanations. It is a theory in a more restricted
sense. According to the simulation alternative, folk psychological explanation
is normative and first personal; it is a matter of finding the other person's
life intelligible `from the inside'. {48} This is an imaginative project; and understanding involves,
not only reasoning in imagination, but also emotion and memory. What is
remembered is, of course, information about psychological matters. So, if
psychological understanding is to range beyond the domain of reason then,
even by the lights of the simulation account, it must draw on psychological
theory. But this does not constitute a victory for the theory theory, because
the psychological theory on which simulation and understanding draw is theory
in the inclusive sense, but not in the restricted sense that is relevant
to the theory theory's account of psychological explanation.

If we do not distinguish the inclusive sense of `theory' which is relevant
to the debate about prediction from the restricted sense of `theory' which
is relevant to the debate about explanation, then we may obscure from ourselves
the role of empathy and emotion in commonsense psychological understanding.

Acknowledgement note

Some of the material in this paper was presented at the Pacific Division
meeting of the American Philosophical Association and at the University
of Michigan, as well as at seminars in Canberra, Melbourne, Oxford, Paris
and Sydney. We are grateful to many friends and colleagues, including Ned
Block, Greg Currie, Allan Gibbard, Robert Gordon, Paul Harris, Jane Heal,
Frank Jackson, Janet Levin, Christopher Peacocke, Philip Pettit, Huw Price,
Peter Railton, Ian Ravenscroft, Michael Smith, Dan Sperber, Stephen Stich
and Kendall Walton, for comments and conversations. MD is pleased to acknowledge
financial support from the Australian National University and the Humanities
Research Board of the British Academy and is especially grateful to the
Philosophy Department at the University of Michigan for the opportunity
to visit as the James B. and Grace J.Philosopher in Residence.

2. T. Nagel, The View from Nowhere
(Oxford: Oxford University Press, 1986), p. 5: `A view or form of thought
is more objective than another if it relies less on the specifics of the
individual's makeup and position in the world, or on the character of the
particular type of creature he is.' {back}

4. The debate (particularly in its early stages)
seems to have been conducted under two assumptions. One is that there is
a single question to be asked about folk psychology. The other is that the
theory theory and the simulation alternative offer the only two viable approaches
to answering that question. But both of these assumptions are flawed. As
against the first assumption, we would say that there are many different,
and fairly independent, questions to be asked about folk psychological practice,
each one of which might be given a theory theory or a simulation theory
style of answer. (See T. Stone and M. Davies, `The Mental Simulation Debate:
A Progress Report', in Theories of Theories of Mind op. cit. note
1, pp. 119-120, for nine such questions. No doubt there are more.) As against
the second assumption, we would make two brief points. One point is that
we cannot simply assume that the two terms, `theory theory' and `simulation
theory', even when quite generously construed, cover the whole space of
possible answers to the questions that are at issue. The other point is
that, even for a single question, and even when the theory theory and the
simulation alternative are the only approaches in view, the correct answer
might be a hybrid, drawing on both approaches. {back}

5. Elsewhere (`The Mental Simulation Debate:
A Progress Report', p. 120), we have put the question this way: `What resources
do mature adult humans draw upon as they go about the business of attributing
mental states, and predicting and explaining one another's mental states
and actions?' We called it the explanatory question about normal adult
folk psychological practice. We have now opted to call it the basis
question lest the term `explanatory' suggest that the question relates only
to the explanation strand of folk psychological practice. {back}

6. The general principle is that pressure
is proportional to (absolute) temperature and inversely proportional to
volume. In the present context, the volume is constant. If, instead, the
temperature is regarded as constant then the resulting principle, that volume
is inversely proportional to pressure, is known as Boyle's law. {back}

7. This kind of prediction by simulation in
imagination is closely connected with the use of thought experiments in
science. Thought experiments are often important in the development of theory,
and so it may seem implausible to say that simulation in imagination draws
on theory. We need to note, once again, that an inclusive notion of theory
is in play, and that in some cases the propositions drawn on will simply
be intuitive assumptions about what kinds of thing do, or do not, tend to
happen in the physical world. See, for example, R. Sorenson, Thought
Experiments (Oxford: Oxford University Press, 1992), pp. 52-4, for an
account of Stevinus's use (in 1605) of a thought experiment to determine
the force needed to keep a ball from moving down an inclined plane. One
of the assumptions at work in this case was that perpetual motion does not
happen. {back}

9. The whisky example is discussed by Jane
Heal, `How to Think About Thinking', in Mental Simulation, op. cit.
note 1, p. 48, and by Richard Moran, `Interpretation Theory and the First
Person', Philosophical Quarterly, 44 (1994), p. 163. The Müller-Lyer
illusion is discussed by Robert Gordon, `Reply to Stich and Nichols', in
Folk Psychology, op. cit. note 1, pp. 175-6. The example of emotional
response to a story is discussed by Kendall Walton, `Spelunking, Simulation
and Slime: On Being Moved by Fiction', in Emotion and the Arts, M.and
S.(eds.) (Oxford: Oxford University Press, 1997), and Ian Ravenscroft, `What
Is It Like to be Someone Else?: Simulation and Empathy', Ratio, 11
(1998). The case of inference is central in Heal's discussions. We take
the example from Allan Gibbard, `Brains, Thoughts, and Norms', unpublished
manuscript. {back}

10. S.and S. Nichols, `Cognitive Penetrability,
Rationality and Restricted Simulation', Mind and Language, 12 (1997),
p. 302, call this `actual-situation-simulation'. It is important to avoid
a possible confusion here. In some important examples, a protagonist has
a false belief about her situation: there is a difference between the situation
as it actually is and the situation as the protagonist takes it to be. A
subject who is asked to predict what the protagonist will think or do may
make an incorrect prediction by focusing on the situation as it actually
is rather than the situation as the protagonist takes it to be. (This is
what very young children tend to do. There is a substantial empirical literature
on the false belief task. See, for example, H.and J. Perner, `Beliefs
About Beliefs: Representation and Constraining Function of Wrong Beliefs
in Young Children's Understanding of Deception', Cognition, 13 (1983),
pp. 103-28.) But this predictive strategy is not what Stich and Nichols mean
by `actual-situation-simulation' (and not what we mean by `simulation in
reality'). Rather, actual-situation-simulation would involve placing myself
into the same situation as the protagonist and making myself (perhaps per
impossibile) subject to the same false belief. {back}

14. See S. Blackburn, `Theory, Observation
and Drama', in Folk Psychology, op. cit. note 1, p. 283: `Theorizing
under a normative umbrella is still theorizing. It could, it seems,
be done quite externally, in the light of a sufficient stock or principles
telling what it would be right or wrong to think or feel in some situation
. . .'. Janet Levin, `Folk Psychology and the Simulationist Challenge',
Acta Analytica, 14 (1995), p. 91, also makes the point that if we
use a normative theory to predict what inferences a person will make then
this does not yet seem to involve anything that is `in any serious sense
a simulation'. {back}

17. The general idea here is familiar from
discussions of the principles involved in radical interpretation. Some advocates
of mental simulation contrast the simulation approach with the rationality
approach, and so would not adopt the account of the epistemology of psychological
prediction that is sketched here. See, for example, Goldman, `Interpretation
Psychologized'. On the other hand, R.M. Gordon, `Simulation Without Introspection
or Inference from Me to You', in Mental Simulation, op. cit. note
1, can be seen as resisting the idea that the epistemology of prediction
by simulation is the same as that of prediction by way of empirical theory.
{back}

18. `Folk Psychology: Simulation or Tacit
Theory?', `Second Thoughts on Simulation', and `Varieties of Off-Line Simulation';
op. cit. note 3. We note again that Stich and Nichols use the term `theory'
in an extremely inclusive sense. {back}

21. In Section 1.3, we noted the similarity
between gas cylinder simulation in reality and the use of experiments to
establish generalisations about how gas cylinders in a certain class generally
behave. The present point, that simulation in reality yields predictions
that are insulated from antecedently held theory, is analogous to the point
that experiments are apt to yield results that conflict with antecedently
held theory. {back}

22. Someone using simulation in reality as
a prediction method may, of course, refuse to accept the result of a simulation
if it conflicts with an antecedently held theory, and may judge that the
simulation must be flawed in some way. The same goes for experimentation.
{back}

23. These two examples are discussed by Stich
and Nichols, `Folk Psychology: Simulation or Tacit Theory?', p. 151, along
with the example of belief perseverance; see R.and L. Ross, Human Inference
(Englewood Cliffs, NJ.: Prentice Hall, 1980), pp. 175-9. In `Second Thoughts
on Simulation', pp. 101-2, they introduce the further example of failure
to predict how subjects will behave in Milgram's obedience experiment. S.
Nichols, S.and A. Leslie, `Choice Effects and the Ineffectiveness of Simulation',
Mind and Language, 10 (1995), pp. 442-4, also discuss an example of
subjects' failure to predict how they themselves will behave when asked
to put a price on an article that they own. {back}

29. See for example, A. Kühberger, J.
Perner, M.and R. Leingruber, `Choice or No Choice: Is the Langer Effect
Evidence Against Simulation?', Mind and Language, 10 (1995), p. 433:
`[I]t is difficult to ensure that simulator participants are provided with
sufficient information about exactly the right combination of factors that
produces the Langer effect.' Kühberger et al. refer to the requirement
that `the imagined situation captures the relevant features of the simulated
person's actual situation' as the requirement of imaginative adequacy
(p. 424). {back}

A theory theorist may object that the use of the wrong inputs response
by the friend of mental simulation is ad hoc and that the defender of the
simulation theory in the face of examples of prediction failure should be
willing to state in advance under what conditions the requirement of imaginative
adequacy would be met. (See Stich and Nichols, `Second Thoughts on Simulation',
p. 102.) But it is not clear that the theory theorist's own approach to
examples of prediction failure is any more principled. The theory theorist's
explanation of prediction failure is in terms of the predictor's use of
an incomplete or false theory about psychological matters, or the predictor's
use of incorrect initial conditions to instantiate correct generalisations.
But no independently motivated account of the exact nature of the predictor's
failure is provided. (This point is made in an unpublished paper by Ian
Ravenscroft, and also by Stich and Nichols, `Cognitive Penetrability, Rationality
and Restricted Simulation', p. 323, who credit it to Meredith and Michael
Williams.) {back}

30. Alternatively, I could drink a pint of whisky
myself, combining simulation of the subject's beliefs in imagination with
simulation of the subject's whisky drinking in reality. This might enable
me to make a correct prediction, if whisky has the same effect on my reasoning
from hypothesised contents as on the subject's reasoning from believed contents.
However, it is important to note that the effects of my drinking the whisky
will not be restricted to my simulation of the subject; my reasoning in
my own person will be perturbed as well. This might be a disadvantage if
I need to think carefully and accurately about how best to act towards the
subject. {back}

32. So-called non-rational influences may
have their effects in a very direct way by-passing reasoning altogether
as, perhaps, in the case of the shoppers. But they may also work by making
something that is not in fact a reason for acting in a certain way nevertheless
appear to be a reason. We are not committing ourselves to any specific account
of the various examples of prediction failure. Indeed, we are not even committed
to the idea that the examples of prediction failure all involve non-rational
influences. Perhaps subjects in the Langer-style experiment have good reasons
for setting their sell-back prices, but those reasons are somehow obscured
from subjects in the prediction experiment. In that case, a defender of
simulation will, in the end, be right to use some version of the wrong inputs
response. What we are pointing out is just that there is a different kind
of response in terms of non-rational influences that is, in principle, available
to the simulation theorist. See J. Heal, `Simulation and Cognitive Penetrability',
Mind and Language, 11 (1996), pp. 60-6. {back}

34. D.and A. Tversky, `On the Psychology
of Prediction', Judgment Under Uncertainty: Heuristics and Biases,
D. Kahnemann, P.and A.(eds.) (Cambridge: Cambridge University Press, 1982),
pp. 67-8. The example was used by Ned Block (in conversation) to make the
objection under discussion here. Essentially the same objection against
Heal's circumscribed version of simulation theory is pressed by Stich and
Nichols, `Cognitive Penetrability, Rationality and Restricted Simulation'.
{back}

36. C. Hempel, Aspects of Scientific Explanation
(New York: The Free Press, 1965), who provides the seminal account of the
deductive-nomological model of explanation, regards the distinction between
prediction and explanation as being merely pragmatic. {back}

37. We are committed to the possibility that
there may be both normative and empirical principles cast in very similar
terms. Both kinds of principle would make use of ceteris paribus
clauses; but those clauses would be interpreted differently in the two cases.
{back}

38. Heal, `Replication and Functionalism',
p. 52. See also, J. McDowell, `Functionalism and Anomalous Monism', in Actions
and Events: Perspectives on the Philosophy of Donald Davidson, E.and
B.(eds.) (Oxford: Basil Blackwell, 1985), p. 389: `[T]he concepts of the
propositional attitudes have their proper home in explanations of a special
sort: explanations in which things are made intelligible by being revealed
to be, or to approximate to being, as they rationally ought to be.' {back}

39. Thus, for example, Gordon, `Simulation
Without Introspection or Inference from Me to You', p. 56, quotes Kant (Critique
of Pure Reason, A353) approvingly: `It is obvious that, if I wish to
represent to myself a thinking being, I must put myself in his place, and
thus substitute, as it were, my own subject for the object I am seeking
to consider (which does not occur in any other kind of investigation).'
For an illuminating discussion of issues not far removed from those of the
present section, see Moran, `Interpretation Theory and the First Person'.
{back}

40. R.G. Collingwood, `Human Nature and Human
History', in The Idea of History (Oxford: Oxford University Press,
Revised Edition 1992), p. 215. As is quite widely remarked, the simulation
approach to psychological understanding has marked affinities with the hermeneutic
tradition of Vico, Herder, Dilthey, Weber and Croce, as well as Collingwood.
See Verstehen and Humane Understanding: Royal Institute of Philosophy
Supplement 41, A. O'Hear (ed.) (Cambridge: Cambridge University Press,
1997). {back}

44. These responses may have consequences,
not only for my reasoning within the scope of my simulation of C, but also
for my reasoning in my own person. Cf. footnote 30 above. {back}

45. If my prediction about C's thoughts and
actions is to count as knowledge then it should not depend on the flawed
normative judgement that this is the thing to think, or to do, in these
circumstances. In this case, knowledgeable prediction seems to require some
recognition of the fact that one's reasoning is indeed being perturbed.
{back}

46. R.M. Gordon, `The Simulation Theory:
Objections and Misconceptions', in Folk Psychology, op. cit. note
1, p. 103. Since understanding is a kind of knowledge, there will once again
be a need for me not to be wholly in the grip of the re-enactment (cf. footnote
45 above). {back}

47. Nichols et al., `Varieties of Off-Line
Simulation', pp. 59-67, discuss empathy and in particular the role of memory
in empathetic emotion. What we are concerned with here, however, is remembered
emotion, not emotion aroused by memory. {back}